package cn.cslg.news.captcha;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

@WebServlet("/vcode")
public class SimpleCaptcha extends HttpServlet {

	private static final long serialVersionUID = -775699744475915178L;
	private Font mFont = new Font("Times New Roman", Font.PLAIN, 18); // ��������

	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doGet(request, response);
	}

	private String genCode() {
		Random rand = new Random();
		rand.setSeed(System.currentTimeMillis());
		StringBuilder buf = new StringBuilder();
		for (int i = 0; i < 6; i++)
			buf.append(rand.nextInt(10));
		return buf.toString();
	}

	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		HttpSession session = request.getSession();
		response.setContentType("image/gif");
		response.setHeader("Pragma", "No-cache");
		response.setHeader("Cache-Control", "no-cache");
		response.setDateHeader("Expires", 0);

		String code = genCode();
		session.setAttribute("VerifyCode", code);

		int width = code.length() * 15, height = 20;

		ServletOutputStream out = response.getOutputStream();
		BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
		Graphics graphics = image.getGraphics();
		Random random = new Random();
		random.setSeed(System.currentTimeMillis());

		graphics.setColor(getRandColor(200, 250));
		graphics.fillRect(0, 0, width, height);

		graphics.setColor(Color.black);
		graphics.setFont(mFont);

		graphics.setColor(new Color(0));
		graphics.drawRect(0, 0, width - 1, height - 1);

		graphics.setColor(getRandColor(120, 200));
		for (int i = 0; i < 155; i++) {
			int x = random.nextInt(width);
			int y = random.nextInt(height);
			int xl = random.nextInt(25);
			int yl = random.nextInt(25);
			graphics.drawLine(x, y, x + xl, y + yl);
		}

		for (int i = 0; i < code.length(); i++) {
			String rand = "" + code.charAt(i);
			graphics.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
			graphics.drawString(rand, 13 * i + 6, 16);
		}
		ImageIO.write(image, "JPG", out);
		out.close();
	}

	static Color getRandColor(int fc, int bc) {
		Random random = new Random();
		if (fc > 255)
			fc = 255;
		if (bc > 255)
			bc = 255;
		int r = fc + random.nextInt(bc - fc);
		int g = fc + random.nextInt(bc - fc);
		int b = fc + random.nextInt(bc - fc);
		return new Color(r, g, b);
	}

}
